The only problem with that is Chandler has outperformed many of the TE's you have rated higher over the past few years. I am not sure I understand your criteria.
Chandler is certainly not elite. He is average to above average. He lacks speed certainly. I would love for the Bills to have an elite TE, but compared to the other FA options this year once Graham and Pitta were locked up, I am fine with Chandler. Finley could be the exception, but he may or may not be healthy, and who knows if wanted to even leave GB. I would rather the Bills focus the draft on a potential #1 WR, OT, OG in that order, and resigning Chandler allows them to do that.
As to TD production, do you think the QB position may have a bit to do with that?